Benefits

What is RGH40?

The RGH40 readhead offers all the benefits of the market proven RG4 linear encoder system - generous installation tolerances and high-speed, non-contact performance with filtering optics to guarantee reliable performance over light oils, dust and scratches.

What is RGS40-G scale?

RGS40-G is a glass spar scale featuring 40 µm pitch incremental graduations in lengths up to 1 m. The spar has an accuracy of better than ±4.1 µm over a 1 m length. System designers can choose between specially formulated adhesive tape or mechanical clips to suit mounting requirements. Both mounting methods allow for independent thermal expansion to that of the substrate.

Why choose this encoder system?

Reliable

The RGH40 readhead is a robust and reliable encoder system with a proven pedigree ensuring low cost of ownership.

Ease of setup

With generous setup tolerances and an integral setup LED offering real-time signal feedback, the RGH40 readhead can be installed quickly and easily.

Dual limit sensing

The RGH40 readhead includes dual limit switch sensing as standard to enable dedicated signals for each end-of-axis indication. A repeatable reference or datum mark also comes as standard.

Direct output

The RGH40 outputs RS422 digital resolutions from 5 µm to 50 nm direct from the readhead without the need for an additional interface.

Interface option

REE interface

Can be used with RGH40A variants only.

The REE accepts industry standard 1 Vpp analogue signals which can be interpolated and output as digital RS422 resolution.

Incorporating automatic gain control (AGC) and unique self-tuning adaptive electronics, the REE, combined with the filtering optics of the readhead, ensures excellent signal integrity, and gives an improved cyclic error over the all-in-one digital readheads.

Case studies

Power Plus offers high precision camera positioning for virtual reality technology in the broadcasting industry, with the help of Renishaw’s optical and magnetic encoders to support accuracy and repeatability.

By virtually every measure of comparison the Airbus A380 ‘Superjumbo’ is the largest commercial airliner in the world. But building such a behemoth calls for some highly innovative technologies that depend upon Renishaw’s RG4 linear encoder systems for positioning accuracy.

How it works

Within the readhead, an infra-red LED emits light laterally onto a scale with reflective and non-reflective areas. The light is directed back off the reflective areas through a transparent phase grating.

This produces sinusoidal interference fringes at the detection plane within the readhead. The optical scheme averages the contributions from many scale graduations and effectively filters out signals not matching the scale period. This ensures signal stability even when the scale is contaminated or slightly damaged.

Low short-term errors are assured by the unique optical design, typically giving less than ±0.30 μm Sub-Divisional Error (SDE). For even lower SDE and even higher signal stability, the analogue version of the RGH40 can be connected to the REE interface which include Auto Gain Control (AGC) and Auto Offset Control (AOC) that operates at all speeds.

The RGH40 readhead features a set-up LED, which lights green when optimum installation has been achieved.

A magnetic reference mark is available with this readhead, providing a unidirectional repeatable zero position.

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